Apparatus for producing sound



April 29, 1930.

E. C. GUEDON APPARATUS FOR PRODUCING sown Filed Aug. 51, 1928 Inventor. Em'l Le C. Guedon,

His Attorney Patented Apr. 29, 1930 UNITED STATES PATENT OFFICE EMJZLE G. GUEDON, OF SCHENEOTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK APPARATUS- ronrnonucme soon]:

Application filed August a1, 1928." Serial No. 303,207.

My invention relates to apparatus for producing sound, and has for its principal ob,

10 have been provided in the past. Many or these apparatus comprise a magnetic armature which is moved in a magnetic field either .in accordance with electrical impulses dependent on sound or in accordance with the 15 contour of a sound record. It is frequently desirable that such an apparatus be so mount ed that it may be moved or rotated to one operating position for use with-the hill-and dale groove type of record and to another operating position for use with thelateral groove type of record. Due to the fact that the undulationsof the hill-and-da-le and lat,- eral grooves are substantially at right angles, however, force is applied to the stylus either in the plane of armature movement or at right angles to this plane depending on the operating position of the apparatus.

When .force is applied to the stylus in the plane of the armature movement, the armature does not move altogether in. accordance with the contour of the record and the sound produced by the apparatus is likely to be distorted. In accordance with my invention, .this difliculty is avoided by the provision of means for equalizing the force applied to the armature in its diflerent operat ing positions.

My invention will be better understood fromv the following description when 'considered in connection with the accompany ing drawings and its scope will be pointed out in the appended claims.

Referring to the drawings, Figs- 1 and 2 illustrate different operating positions of a sound producing apparatus wherein my invention has been embodied; and Figs. 3, 4 and 5 illustrate various details of. the apparatus.

This apparatus includes a sound producing or magnetic pick-up device 1 which is mounted on a. support 2 so that it can'be rotated either. into the operating position illustrated by Fig. l for use with a lateral groove sound record or into the position illustrated by Fig. 2 for use with a hill-and-dale groove sound record. As indicated by Figs.-1 and 2, an ordinary steel needle is used in connection with the lateral groove record and a special diamond point stylus holder is used in connection with the hill-and-dale groove record.

As shown more clearly by Figs. 3' and 45,

the sound producer or pick-up device I includes a magnet 3 provided With bifurcated pole pieces 4 and 5 'between which an armature 6-is mounted. This armature is pivotedat 7, is surrounded at its central portion by an operating coil 8, is provided at its lower end with a recess'and a stylus clamping screw 9 and has one of its ends in contact with aresilient block 10 whereby it tends to be maintained in its-mid or neutral position.

The operation of the device is well understood by those skilled in the art and need not be described in detail. As the stylus follows the contour of the groove in the sound record, the upper or free end of the armature is moved to and fro between the upper projections of the pole pieces, thus reversing the flux in the coil 8 and producing therein a current dependent on the contour of the groove.

,So long-as the device 1 is in the operating position illustrated by Fig. 1, its weight is applied to the stylus in a plane at right angles to the motion of the armaturefi and does not tend to move the armature out of its central or neutral position.

When the device 1 is in the operating posi- -tion illustrated by Fig. 2, however, its-weight is applied to the stylusin a direction along the'plane in which the armature moves and the armatureno longer tends to return to its neutral position.

In the illustrated embodiment of the invention, this difficulty is avoided by the provision'of a resilient member or spring 11 which is attached to the pole piece 5 at one of its ends, is provided with a prong-shaped projection at the other of its ends, and has an opening surrounding the lower end of the armature 6. In the operating position illustrated by Fig. 2, pressure for neutralizing the weight of the device 1 is applied the This projection fits into the bifurcated or 'prong-shaped projection in the end of the lower end of the armature.

spring and in order that the spring may always exert the sameequalizing pressure, the diamond point stylus holder is grooved at the side as shown in Fig. 5, so that tightening of the screw 9 always causes it to be drawn tightly against the top, of the recess in the It will be readily understood that if the diamond point is mounted on the projection 12, the necessity of rotating the device 1 is avoided.

, In order to facilitate the placing of the stylus in contact with a sound record, it is desirable that the stylus be easily seen. This result is achieved in the illustrated embodiment of my invention by cutting away the corners of the pole pieces so that the stylus 5. In a sound producing device arranged to be moved into different operating posi-.

the other of its ends for applying to said armature a force whereby the effect of said Weight on said armature is neutralized.

In witness whereof, I have hereunto set my hand this 30th dayof August, 1928.

EMILE G. GUEDON.

protrudes from near the junction of converging sides of the device.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a sound producing device arranged to be moved into different operating posi- I tions, a movable armature arranged to be unafiected by the weight of said device in one of said positions and to be affected by said Weight in another of said positions, and

means for neutralizing the effect of said weight on said armature in said last mentioned position.

' 2. In a sound producing device arranged to be moved into diiferent operating positions,

a movable armature arranged to be unaffected by the Weight of said device in one of said positions and to be afiected by said weight in another of said positions, and a spring for neutralizing the effect of said weight on said armature in said last mentioned position.

3. In a sound producing device arranged to it be moved into different operating positions, means for producing a magnetic field, an armature arranged to move in said field and to be affected by the weight of said device in one of said positions, and resilient means attached to said magnetic means for neutralizing the efiect of said weight on said armature.

4. In a sound producing device arranged to be moved into different operating positions, means for producing a magnetic field, an armature arranged to move in said field and to be affected by the weight of said device in one of said positions, resilient means attached to said magnetic means for neutralizing the effect of said weight on said armature, and means for predetermining the neutralizing force applied to said armature through said resilient means. i 

